As the Year 2000 nears, concern about possible problems caused by computer glitches is increasing, and contingency planning is shifting -- some say belatedly -- into high gear. Companies and governments are identifying ways to work around power failures and disruptions of food supplies. Some experts even say that computers not programmed to read “2000” could trigger a worldwide recession. U.S. officials are cautiously optimistic that basic infrastructure systems won't shut down. But small businesses and many foreign countries lag far behind in their Y2K repairs. Given the interconnectedness of today's wired world, some observers fear that weak links in the global computer network could cascade into massive disruptions in power, telephone and water services.